In 3GPP (3rd Generation Partnership Project), currently, specifications of LTE-A (Long Term Evolution-Advanced) are studied. LTE-A has been requested to realize higher-speed communication than LTE. Therefore, it has been decided that LTE-A supports a wider band (beyond the 20 MHz band of LTE, up to the 100 MHz band) than LTE.
In LTE-A, carrier aggregation (CA: Career Aggregation) technology is employed for the purpose of maintaining compatibility with LTE as much as possible. The carrier aggregation technology is a technology such that a plurality of frequency bands each having a bandwidth up to 20 MHz, which are called component carriers (CC), are used to collectively perform communication, thereby ensuring a bandwidth up to 100 MHz, and thus realizing high speed communication with large capacity (see section 5.5 of Non-Patent Document 1).
Regarding the CA, depending on use of frequency bands to be used, there are three methods.
(1) the same contiguous frequency bands are used (Intra-band Contiguous CA).
(2) the same dispersed frequency bands are used (Intra-band Non-Contiguous CA).
(3) Different frequency bands are used (Inter-band Non-Contiguous CA).
A conventionally-studied CA technology is a CA technology among mobile stations and one macrocell base station. The CA communication technology has a feature that PUCCH (Physical Uplink Control Channel) is transmitted from a mobile station using one CC. The agreement that PUCCH is transmitted using one CC has been made for the two following reasons.                If PUCCH is transmitted using a plurality of CCs, PAPR (Peak to Average Power Ratio) and current consumption increase, and the load on a battery of the mobile station increases. For this reason, PUCCH is transmitted using one CC.        In a case where the same contiguous frequency bands are used (above (1)), bands used to transmit PUCCH are adjacent to each other, thereby occasionally causing a spurious signal to be generated. For this reason, PUCCH is transmitted using either one of CCs.        
CC used to transmit PUCCH is defined as a PCC (Primary Component Carrier), and CC not used to transmit PUCCH is defined as SCC (Secondary Component Carrier). Additionally, it has been agreed not to transmit PRACH (Physical Random Access Channel) in SCC. In other words, the CA communication here refers to a communication system in which a plurality of frequency bands are used to perform transmission and reception, but PUCCH is transmitted using only one CC.
In multicarrier communication, such as cooperative communication (COMP; also referred to as Coordinated Multi-Point Transmission/reception) or MIMO (Multiple Input Multiple Output), PUCCH can be transmitted from each of a plurality of antennas of a mobile station, that is, using respective ones of a plurality of frequency bands. For this reason, there has been no concept, such as PCC/SCC defined in the carrier aggregation, and it has been possible to use the same signal in two frequency bands independently.
Additionally, in the conventional multicarrier communication, in a case where a new frequency band is added, PRACH (Physical Random Access Channel) is transmitted using that frequency band to be added, synchronization is performed, and a connection process is performed, thus adding the frequency band. It has been possible to use a PRACH signal in any frequency band independently.
In the CA communication, the connection process is also different from that for the multi-carrier communication, and it is limited to PCC, which is a first frequency band, that can use a PRACH signal (see Section 7.5 of Non-Patent Document 1).